Volume 21 Issue 4 December 2007 erfu w l o P r P o ns nghor Let’s Talk About… Pronghorns Have you seen a pronghorn in Idaho? If you did, you were most likely not in the northern part of our state. Pronghorns are animals that like wide open spaces. They are usually found on grasslands and shrubby areas where the plants don’t get much over two feet high. Pronghorns love the sagebrush in southern Idaho. This is their main source of food in the winter. In the summer, they will also eat soft-stemmed plants, like wildflowers. They don’t like to eat much grass. You may also hear people call pronghorn antelope. Pronghorns may look like the antelope that roam the African plains, but they are really very different animals. Pronghorns are in the family Antilocapridae (an-til- o-CAP-ri-day). They are the only member of this family. They have no close relatives. Pronghorns are beautiful animals. Their upper bodies are pale tan to reddish tan. Their sides, bellies, insides of the legs, and rump are white. They have two broad white bands across their throats. Both the males and females have horns, but the females’ horns are short; they are about four inches long. The males’ horns are longer, being 12 to 20 inches long. They also have a forward pointing, short branch called a “prong.” This is where the name pronghorn came from. The males also have a black band on the snout and black neck patch that the females do not have. Pronghorns are small compared to other hoofed animals. The males weigh between 90 to 140 pounds; females weigh between 75 to 105 pounds. Pronghorns are the fastest animals on North America. They can run 45 miles-per-hour over a long period of time! That doesn’t mean they don’t have predators though. Coyotes eat more pronghorns than any other animal. Bobcats are also predators that might catch a young pronghorn. Catching a healthy adult pronghorn is no easy feat. They have excellent hearing and a good sense of smell. But their eyesight is amazing! A pronghorn’s eyeball is about one and one-half inches in diameter. That’s the size of a horse’s eye! Pronghorns can see something moving when it is up to four miles away! You might say they have built-in binoculars. Although pronghorns can detect a moving object miles away, they may ignore a person standing still just fifty feet away. Things need to move for a pronghorn to see it. When pronghorns spot danger, they have a way to warn other pronghorns. They stick up the white hairs on their rumps. On a bright day, the signal may be seen for miles. This is a cue for other pronghorns to do what they do best – run. Keep an eye out for pronghorns. They have been known to be playful at times. Pronghorns have even raced vehicles driving on roads through their habitat. Built For Speed Ungu-What? If a pronghorn and a cheetah were in a Pronghorns are ungulates (UN-gyu-lits). race, which animal would win? The cheetah is a faster Ungulate is the Latin word for hoof. All ungulates sprinter. It would win in a short-distance race, but the have hooves. pronghorn would win a long-distance race. It would still be going long after the cheetah stopped. Scientists used to group all ungulates together, but now they are divided into two groups. One group Pronghorns’ bodies are made for speed and includes animals that have an odd number of toes. endurance. Their hearts, lungs, and the tubes that carry oxygen to their lungs are two to four times larger than Horses are in this group. Animals in the other group a similar sized animal, like a goat. Their blood has lots have an even number of toes. Which group do you of hemoglobin (HEE-mo-glow-bin) in it. Hemoglobin think pronghorn are in? is what makes your blood red. Oxygen binds to hemoglobin and the hemoglobin carries the oxygen All ungulates are herbivores. They eat plants. to the muscles. The more hemoglobin an animal has, Grasses, leaves and twigs are tough to eat. To help the more oxygen it can carry to its muscles, and the them digest plants, ungulates have stomachs divided faster its muscles can work. The muscles are also into four different chambers or rooms. packed with many mitochondria (my- toe-KON-dree- a). Mitochondria are like power plants. They turn food When pronghorns eat, they nip off leaves from into energy, so the more mitochondria a muscle has, the shrubs. They don’t chew their food much before faster it can work. Pronghorn also have thick leg bones; swallowing it. The leaves go into the first chamber of they are twice as thick as a cow’s leg bone. Those their stomachs. The first chamber is full of bacteria thick bones let pronghorns run over rough land without and other organisms that help break down the plants. breaking their legs. Later, pronghorns spit up the food and chew it All these adaptations allow pronghorns to be the again. Have you ever heard of cows chewing their fastest mammal in North America. They have bursts cud? They are chewing food regurgitated from their of speed that are greater than 60 miles-per-hour, and stomachs. they can sustain speeds of 30 to 45 miles-per-hour over long distances. Some people wonder why a pronghorn Once chewed, the food passes into the second would need to run so fast. After all, cheetahs don’t and third parts of their stomachs where water is taken live in North America. Well, they once did! Ancient out of the food. The fourth chamber of their stomachs pronghorns were hunted by cheetahs! Saber-toothed is the one that is most like your stomach. It absorbs cats, lions and the American cheetah once roamed the nutrients out of the food. North America. The pronghorn would have been a tasty treat for those big cats. Pronghorns that ran slow Having a stomach with many chambers not were eaten, but those that ran quickly got away. Nature only allows animals to eat tough plants, it also selected fast pronghorns. American cheetahs may be helps to keep them safe. Many animals are at risk extinct, but pronghorns are still here with their bodies when they eat. Predators are more likely to see a built for speed. deer eating in a clearing than hiding under a tree, so deer eat quickly. They nip off plants, chew them just a little and then swallow them. Once their first stomach is full, the deer finds a place to rest and hide. Now the deer can fully chew and digest their food, without having to constantly look out for danger. Don’t ungulates have some amazing adaptations? 2ENAI#"ROGDON )$&' Horns Bison, pronghorns and bighorn sheep have horns. Horns are a bit different than antlers. Horns have two parts, a boney middle and an outer sheath. The inside part is bone that is attached to the skull. The outside of the horn, the sheath, is a covering made of a tough fiber-like material called keratin. Your fingernails and hair also contain keratin. What purpose does the sheath serve? It protects what’s underneath! Horns are permanent. In most cases, they continue to grow throughout an animal’s life. Pronghorns are an exception to this rule. A pronghorn will shed and re-grow its sheath each year. If you take a close look at most horns, you may see rings. A mountain goat’s horns have rings around them. Counting the rings will tell you how old the goat is. Rings are formed each year after the goat is one year old, so the horns of a mountain goat will have one less ring than its age. Both males and females can grow horns. Antlers are usually only grown by males. Caribou is the exception. Antlers often look like tree branches with a main beam and points coming off of the beam. Horns are usually not branched like antlers. Growing Up Pronghorn Pronghorn does (females) might have their first baby (fawn) when they are about one and one-half years old. Bucks (males) are usually around three years old before they breed. In mid-summer, breeding males stake out territories. They mark their territories by rubbing scent glands on the sides on their necks on plants and by making loud snorts. They will also paw at the ground to tell other males to stay away. They will defend their territories from all other males, but females can travel between the males’ territories freely. At this time, the bucks start to gather groups, or harems, of females. One buck might have as may as 20 does in his harem. These are the does that buck will breed with. In late summer and early fall, bucks start to show-off for the does. They have mock battles. Sometimes bucks even challenge an imaginary rival! A doe is pregnant for about 250 days. The young pronghorns are born in May or June. The first time a doe has a baby she will probably have one fawn, but after that she usually will have twins. Newborn pronghorns weigh about as much as a human baby – between five to nine pounds. Fawns have a gray coat until they are about three months old. The gray coat helps the fawns camouflage, or hide, from danger. They have no odor and will lie motionless for hours while their mothers are away eating.